Tom Williams/Roll Call/Getty Images(WASHINGTON) -- Liz Cheney announced on Tuesday that she intends to seek the Republican nomination for Senate in Wyoming, taking the rare step of challenging a sitting incumbent, Sen. Mike Enzi.

Cheney, the 46-year-old daughter of former Vice President Dick Cheney, moved to Wyoming last year with her family to eye political opportunities.

She had hoped Enzi would retire, but when he announced his re-election, she signaled that she would join him, setting up a contentious Republican primary fight. And top Republicans were already circling the wagons around Enzi shortly after Cheney’s announcement.

“Obviously I’m going to support senator Enzi,” Senate Minority Leader Mitch McConnell, R-Ky., said on Tuesday. “He’s done an excellent job and no question we’ll be supportive of our incumbent. He’s been a team player.”

And Sen. John Barrasso, Enzi’s fellow senator from Wyoming, also expressed his support for the three-term incumbent lawmaker.

“Mike Enzi is a friend, a mentor, and a tremendous U.S. senator,” he said, “and I plan to support his re-election.”

A strategist at the National Republican Senatorial Campaign Committee also signaled that Cheney would face an uphill battle when it comes to the Republican establishment.